smbios: Add generic type41 write function

Mainboards were defining their own SMBIOS type41
write function.  Instead pull this into the generic
SMBIOS code and change the existing mainboards to
make use of it.

Change-Id: I3c8a95ca51fe2a3118dc8d1154011ccfed5fbcbc
Signed-off-by: Duncan Laurie <dlaurie@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/56619
Reviewed-by: Stefan Reinauer <reinauer@google.com>
Reviewed-on: http://review.coreboot.org/4187
Tested-by: build bot (Jenkins)
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>

src/include/smbios.h

@@ -8,8 +8,14 @@ unsigned long smbios_write_tables(unsigned long start);
 int smbios_add_string(char *start, const char *str);
 int smbios_string_table_len(char *start);
 
+/* Used by mainboard to add an on-board device */
+int smbios_write_type41(unsigned long *current, int *handle,
+			const char *name, u8 instance, u16 segment,
+			u8 bus, u8 device, u8 function);
+
 const char *smbios_mainboard_manufacturer(void);
 const char *smbios_mainboard_product_name(void);
+
 const char *smbios_mainboard_serial_number(void);
 const char *smbios_mainboard_version(void);
 void smbios_mainboard_set_uuid(u8 *uuid);